Storage tank for viscous fluids



Oct. 6, 1964 B. BUCHNER ETAL 3,151,768

STORAGE TANK FOR VISCOUS FLUIDS Filed March 6, 1963 BERNARD BUCHNER ALFRED HORAX Jn renfor:

BY 0 g3 AGENT United States Patent 3,151,768 STORAGE TANK FOR VISCGUS mums Bernhard Biichner, lngolstadt, and Alfred Horalr, Bittenbrunn, near Neuburg, Germany, assignors to Auto Union G.m.h.H., Ingoistadt, Germany, a corporation of Germany Filed Mar. 6, 1963, Ser. No. 263,283 Claims priority, application Germany Mar. 8, 1962 8 Claims. (Cl. 22086) Our present invention relates to a storage tank for oil and similar viscous fluids, more specifically to a tank adapted to be used in an automotive vehicle.

In certain automotive systems, especially those of the two-cycle type, a mixture of fuel and lubricating oil is fed to the cylinders of the internal-combustion engine. Since the preparation of an oil/ gasoline mixture suitable for storage in the vehicular fuel tank is a time-consuming operation, it is desirable to provide a separate storage tank from which the oil to be admixed with the fuel is continuously drawn during operation of the engine. Such oil-storge tanks are preferentially disposed in the vicinity of the exhaust pipe so that the oil will be preheated and maintained at suitable viscosity when the engine is running. On start, however, the oil is usually cold so that the heat transfer from the exhaust gases causes a considerable change in its volume as also in the volume of the air within the tank. These volume changes, as well as the progressive lowering of the oil level during operation require that the tank be in constant communication with the atmosphere through one or more vents which, however, must be so located that no oil is spilled even when the vehicle is in an inclined position. Naturally, it is also desirable for reasons of economy, access to other parts and limitation of weight to make the volume of the tank only as large as is necessary to store the required amount of oil.

The object of our present invention is to provide a storage tank of this character which, while satisfying the foregoing desiderata, can be rapidly filled by hand to a predetermined level with maintenance of sufficient air space to insure that the initial expansion of the oil during engine warmup will not cause the oil to overflow.

These objects are realized, in accordance with the present invention, by the provision of a tank in the form of a preferably prismatic, horizontal container provided at the top with an inlet aperture which accommodates with close fit, thus without external clearance, a substantially vertical inlet pipe terminating short of the container bottom. On the enclosed lower part of the inlet pipe we provide two holes, or sets of holes, at difierent levels, the hole or holes at the lower level being relatively Wide whereas the hole or holes at the upper level are relatively narrow and will be hereinafter referred to as pinholes. The location of the pinhole (or pinholes) should be just below the container top, the wider hole (or holes) being located some what below the normal maximum level of the oil. Thus, oil entering the inlet pipe in a continuous flow will at first expel the air from the container by way of the larger hole or holes until these are covered by the rising liquid; since the air can now escape only through the pinhole or pinholes, its rate of flow is rapidly throttled and it will rise sharply in the inlet pipe until it reaches its neck whereupon the supply will be cut oil by the operator. Subsequently, the escape of air through the pinholes will enable a gradual equalization of the liquid levels in the container and the pipe so that the oil column within the pipe drops to a level well below the mouth of the pipe or any vent opening provided near its top. This creates a safety margin so that impact, vibration and/ or inclina- "ice tion of the vehicle will not drive the oil level back to the region of the vent or the pipe mouth.

We have found that, in practice, the total area of the larger air holes should range between approximately four and eight times the total area of the pinholes when the device of the invention is used with lubricating oils of the type conventionally admixed with the fuel of twocycle internal-combustion engines.

The invention will be described in greater detail with reference to the accompanying drawing whose sole figure represents a side-elevational view (partly in section) of an embodiment of our improved storage tank.

The figure shows a container 1, in the shape of a horizontal sheet-metal prism, whose ends are sealed by two flanged wall elements 2, 3 respectively embraced by and embracing the prismatic container Wall. The members i, 2 and 3 are permanently joined together, preferably by arc welding in a shield gas such as argon. The container is formed at its top surface 4 with a circular inlet aperture 8 framed by an upstanding flange 5 which is integral with the container wall. An inlet pipe 6 extends downwardly through aperture 8 into the container and is held spaced from its bottom by a stirrup 11 secured to the lower pipe end by rivets 14. A ring member 7 of generally U-shaped cross-section closely surrounds the flange 5 so as to form an annular gutter or trough, this ring being welded onto flange 5 and pipe 6 along a common annular seam 9. Thus, the entire unit 1-7 is fused into a solid body resistant to impact, vibration and thermal stresses, the interior of this body being sealed against the atmosphere everywhere except at the inlet pipe 6 and an outlet pipe 15 including a force pump 16.

The neck of pipe 6 has a vent 10 just below the rim of a cap 17 forming a removable closure thereon. The lower part of pipe 6 is formed, at a location just below container surface 4, with one or more pinholes 12 (only one shown) communicating with the interior of container 1. Farther down, below the level of the pinholes, this part has one or more larger holes 13 (only one shown) also opening into the container. The distance between the levels of holes 12 and 13 is advantageously so selected that the container volume encompassed within these levels substantially equals the volume of pipe 6 between the levels of hole 13 and vent it).

It, with cap 17 removed, oil is poured into pipe 6 in a continuous flow, the liquid will accumulate rapidly both in the pipe and in the container itself until its level has risen past the hole 13. Thereupon, owing to the reduced rate at which the displaced air can now escape from container 1 by way of pinhole 12 only, the column of oil in pipe 6 quickly advances toward the mouth of the pipe, or at least to the vent 10, whereupon the operator will discontinue the supply. The remaining air trapped in the container will slowly bubble out through pinhole 12 so that the head of liquid present in pipe 6 will gradually drop while the level in the container rises toward the surface 4. With the aforestated proportioning of the parts, the liquid in the pipe and in the container will eventually find a common level in the vicinity of pinhole 12.

When the cap 17 has been replaced, pipe 6 continues to communicate with the atmosphere via vent 10 without any risk of sp llage of oil through that vent one the liquid level in the pipe has dropped as described above. Should the filling have been too hasty, any accidental overflow would have been caught by the trough 7.

Modifications of the specific embodiment described and illustrated are, of course, possible without constituting departures from the sp rit and scope of the invention as defined in the appended claims.

We claim:

1. A manually fillable storage tank for viscous fluids, comprising a container that is substantially closed except for an outlet near its bottom and a filling aperture at its top, and an inlet pipe fitting closely in said inlet aperture and extending downwardly through it into said container with spacing from the bottom of the latter, the lower part of said pipe enclosed by said container being provided with at least one pinhole at a first location just below the container top and with at least one air hole substantially larger than said pinhole at a second location below said first location and above the bottom of the pipe, said locations being spaced apart by a distance such that the volume of said container between said locations is substantially equal to the Volume of said pipe between said second location and the top of said pipe.

2. A tank as defined in claim 6 wherein said container is provided with an upward annular flange surrounding said aperture, said pipe being joined to said flange.

3. A tank as defined in claim 2, further comprising an annular trough member closely surrounding said flange.

4. A tank as defined in claim 3 wherein said trough member, said flange and said pipe are welded to one another by a single annular seam.

5. A tank as defined in claim 6, further comprising a removable cap on the upwardly projecting part of said pipe, said upwardly projecting part being provided with an air vent below said cap.

6. A manually fillable oil tank for automotive vehicles comprising a container that is substantially closed except for an outlet near its bottom and a filling aperture at its top, an inlet pipe fitting closely in said inlet aperture and extending downwardly through it into said container with spacing from the bottom of the latter, and an oil pump powered by the vehicle engine connected to said outlet, the lower part of said pipe enclosed by said container being provided with at least one pinhole at a first location just below the container top and with at least one air hole substantially larger than said pinhole at a second location below said first location.

7. An oil tank as defined in claim 6 wherein said container is substantially in the form of a horizontal prism, said pipe having a diameter smaller than the Width of said prism.

8. An oil tank as defined in claim 6 wherein the area of said air hole is substantially four to eight times that of said pinhole.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A MANUALLY FILLABLE STORAGE TANK FOR VISCOUS FLUIDS, COMPRISING A CONTAINER THAT IS SUBSTANTIALLY CLOSED EXCEPT FOR AN OUTLET NEAR ITS BOTTOM AND A FILLING APERTURE AT ITS TOP, AND AN INLET PIPE FITTING CLOSELY IN SAID INLET APERTURE AND EXTENDING DOWNWARDLY THROUGH IT INTO SAID CONTAINER WITH SPACING FROM THE BOTTOM OF THE LATTER, THE LOWER PART OF SAID PIPE ENCLOSED BY SAID CONTAINER BEING PROVIDED WITH AT LEAST ONE PINHOLE AT A FIRST LOCATION JUST BELOW THE CONTAINER TOP AND WITH AT LEAST ONE AIR HOLE SUBSTANTIALLY LARGER THAN SAID PINHOLE AT A SECOND LOCATION BELOW SAID FIRST LOCATION AND ABOVE THE BOTTOM OF THE PIPE, SAID LOCATIONS BEING SPACED APART BY A DISTANCE SUCH THAT THE VOLUME OF SAID CONTAINER BETWEEN SAID LOCATIONS IS SUBSTANTIALLY EQUAL TO THE VOLUME OF SAID PIPE BETWEEN SAID SECOND LOCATION AND THE TOP OF SAID PIPE. 